Device for undulating a pipe

ABSTRACT

A device for imparting an undulation to a smooth pipe ( 1 ) composed of metal which has wave peaks and wave valleys extending transversely relative to the longitudinal direction of the pipe. The device has an undulating unit ( 2 ) with a protrusion which rotates in the circumferential direction in the position of operation for producing the undulation. Arranged in front of the undulating unit ( 2 ) is a guide sleeve ( 5 ) for guiding the smooth pipe ( 1 ) moved in its longitudinal direction. A support sleeve ( 7 ) is arranged immediately behind the undulating unit ( 2 ) which tightly surrounds the undulated pipe ( 6 ) which leaves the undulating unit ( 2 ) in the pulling off direction without impairing the movement of the undulated pipe ( 6 ) in its longitudinal direction.

RELATED APPLICATION

This application claims the benefit of priority from European Patent Application No. 13 305 005.4, filed on Jan. 7, 2013, the entirety of which is incorporated by reference.

BACKGROUND

1. Field of the invention

The invention relates to a device for imparting an undulation to a smooth pipe composed of metal, wherein, in the position of operation, the undulation extends transversely of the longitudinal direction of the pipe with wave crests and wave valleys extending in the circumferential direction of the pipe, which has an undulating unit with a projection producing the undulation, and in which a guide sleeve is mounted for guiding the smooth pipe travelling in its longitudinal direction (EP 1 084 774 B1).

2. Description of Related Art

Such a device is used for manufacturing pipes of metal having a good bending capability, for example of steel, of copper, or of aluminum. For example, such pipes can be used in building electrical or optical cables or as electrical conductors of high frequency cables, or for transporting flowable media. The undulation can be constructed to be shaped helically or ring-shaped. The degree of bending capability depends substantially on the depth of the undulation, i.e. on the radial difference between the wave crests and the wave valleys.

In the known device according to the above mentioned EP 1 084 774 B1 a pipe is formed of a longitudinally entering metal strip which is welded at a longitudinal slot. The resulting smooth pipe is subsequently undulated transversely of its longitudinal direction in an undulating unit. A guide sleeve whose internal diameter is virtually the same as the external diameter of the smooth pipe, called an undulating sleeve, is arranged immediately in front of the undulating unit equipped with an undulating disk. The undulated pipe emerging from the undulating unit is moved by means of an elongated hollow shaft connected to the undulating unit, wherein the hollow shaft is connected so an electric motor. The hollow shaft surrounds the undulated pipe at a distance.

OBJECT AND SUMMARY

The invention is based on the object of configuring the device described above in such a way that the dimensions of the undulated pipe are maintained, particularly also in a relatively deep undulation, with increased accuracy of shape or roundness.

This object is met in accordance with the invention by arranging a support sleeve immediately following the undulating unit, which support sleeve tightly surrounds the undulated pipe which leaves the undulating unit in a pulling off direction without impairing the movement of the pipe in its longitudinal direction.

The support sleeve, which may be short in the axial direction, constitutes a kind of fixed point for the pipe already during the undulating process, during which a significant load is applied to the pipe in the radial direction. The support sleeve ensures that the pipe cannot already depart in the radial direction from its desired central position during undulating, or particularly after leaving the undulating unit. As a result, the pipe leaving the undulating unit and moving in the pulling off direction has a uniform or constant undulation and uniform or constant dimensions. Because of the very precise guidance of the pipe through the support sleeve and after undulating, pipes with thin walls can be undulated with particular advantage, and it is also possible to produce a deeper undulation which is of significance for undulation of thin-walled pipes. The support sleeve resting tightly against the undulated pipe has the further advantage that the guide sleeve mounted in front of the undulating unit does not have to rest tightly against the smooth pipe, but may have a greater internal width as compared to the outer diameter of the smooth pipe.

BRIEF DESCRIPTION OF THE DRAWINGS

An embodiment of the subject matter of the invention is illustrated in the drawings. In the drawing:

FIG. 1 schematically illustrates an arrangement for manufacturing an undulated pipe.

FIG. 2 shows on a larger scale a device, according to the invention, which can be used in the arrangement according to FIG. 1.

DETAILED DESCRIPTION

Using an arrangement according to FIG. 1, a smooth pipe 1 of metal is to be provided with an undulation which extends transversely of its longitudinal direction. The manner of manufacturing the pipe 1 is insignificant in this context. The pipe may be, for example, of steel or copper or aluminum. The undulation to be produced in an undulating unit 2 can be constructed ring shaped or helically shaped.

For example, the pipe 1 is moved by means of an only schematically illustrated pulling off device 3 in the direction of arrow 4 and, as a result, the pipe 1 is moved in the direction of arrow 4 which is thereby pushed in the illustrated embodiment through the undulating unit 2. As seen in the pulling off direction, a guide sleeve 5 is arranged in front of the undulating unit 2 through which the smooth pipe 1 is guided. The undulated pipe 6 leaving the undulating unit 2 in the pulling off direction is guided by a support sleeve 7 which is arranged immediately following the undulating unit 2. The undulated. pipe 6 can be wound onto a coil 8.

In the following, the invention will be explained in more detail with the aid of FIG. 2:

The undulating unit 2 used in the device is basically known. Accordingly, only those portions of the device required for the understanding of the invention are explained. The undulating unit 2 includes an undulating head 9 which is constructed as a ring shaped disk with a central opening. In the central opening, an undulating disk 10 is rotatably mounted, for example, by means of a ball bearing 11. The undulating disk 10 has a radially inwardly projecting protrusion 12 by means of which during operation of the device the undulation is compressed into the smooth pipe 1.

In accordance with FIG. 2 the undulating disk 10 is arranged eccentrically relative to the axis A of the pipe 1 or the undulated pipe 6. Accordingly, the axes of the undulating disk 10 and the pipes 1 or 6 extend parallel to each other at a distance from each other. During operation of the device, the undulating head 9 and the undulating disk 10, taken along by the undulating head 9, are rotated in the circumferential direction about the pipe 1. In this connection, the protrusion 12 of the undulating disk 10 presses the undulation into the pipe 1 which is simultaneously pushed in the direction of arrow 4 through the undulating unit 2.

The support sleeve 7 is arranged immediately adjacent, or in the pulling off direction behind the undulating unit 2, namely concentrically with the axis A of the pipe 1 or 6. For example, the support sleeve 7 may also be connected to the undulating head 9, specifically with such a tightness that it is rotated together therewith or rotatable through a bearing, so that the support sleeve 7 is not rotated together with the undulating head 9. However, the support sleeve 7 can also be mounted on the undulating head 9 without being attached to the undulating head 9. The support sleeve 7 may be of synthetic material, such as polyethylene or polyamide, but also of metal, for example, a bronze alloy.

The support sleeve 7 surrounds the undulated pipe 6 as tightly as possible without, however, being in such tight contact that the movement, of the undulated pipe 6 is impaired in its longitudinal direction. Because of the function of the support sleeve 7, the support sleeve 7 already constitutes a type of fixed point for the undulated pipe 6 because the pipe is held in a central position during the undulating process and also thereafter by means of the support sleeve 7. Because of this function of the support sleeve 7, it is no longer necessary that the guide sleeve 5 rests tightly on the smooth pipe 1. This is indicated in FIG. 2 by an air gap between pipe 1 and guide sleeve 5. The guide sleeves does not participate in the rotation of the undulating unit 2. Accordingly, the guide sleeve 5 is supported relative to the undulating unit 2 through a roller bearing 13.

Advantageously, the support sleeve 7 is relatively short in the axial direction. For example, it can have a width which in the case of an annular undulation is equal approximately to the distance between two successive wave crests or in the case of a helical undulation, the distance is approximately equal to twice the undulation pitch. 

What is claimed is:
 1. Device for imparting an undulation to a smooth pipe having metal which extends transversely of the longitudinal direction of the pipe with wave peaks and wave valleys extending in a circumferential direction of the pipe, said device comprising: an undulating unit with a projection which has a protrusion rotating in the circumferential direction in the position of operation, wherein in front of the undulating unit a guide sleeve is mounted for guiding the smooth pipe which is moved in the longitudinal direction of the pipe, and wherein a support sleeve is arranged immediately following the undulating unit which tightly surrounds the undulated pipe leaving the undulating unit in the pulling off direction without impairing the movement of the pipe in its longitudinal direction.
 2. Device according to claim 1, wherein, in the case of an annularly undulated pipe, the axial width of the support sleeve equals approximately the distance between two successive wave crests.
 3. Device according to claim 1, wherein, in the case of a helically undulated pipe, that the axial width of the support sleeve equals approximately twice the undulation pitch.
 4. Device according to claim 1, wherein the support sleeve is tightly connected to an undulation head of the undulating unit, wherein the undulation head is rotatable about its axis.
 5. Device according to claim 1, wherein the support sleeve is connected to an undulation head with the intermediate arrangement of a roller bearing, wherein the undulation head is rotatable about its axis. 